This program will explore how we investigate the most challenging undiagnosed diseases by integrating deep clinical insight with advanced genomic science. It will walk through our comprehensive approach—from detailed medical record review and iterative sequence reanalysis to cutting-edge technologies such as RNA sequencing, long-read sequencing, epigenetics, proteomics, and metabolomics. The talk will highlight how we address the frontier of non-coding regions of the genome, apply functional modeling in vitro and in animal systems to interpret variants, and collaborate through global tools such as Matchmaker Exchange. A central theme of the talk will be the power of networking among investigators across the NIH Undiagnosed Diseases Network nationwide, enabling rapid data sharing, collective expertise, and accelerated discovery. At the heart of this work is close partnership with patients and families, who are true collaborators in the journey of discovery.

Dr. Sweetser is an internationally recognized leader in medical genetics, biochemical genetics, and rare genetic disorders. He has served as Chief of the Division of Medical Genetics and Metabolism at Massachusetts General Hospital since 2011 and holds the Lewis and Leslie Holmes Chair in Genetics and Teratology. Under his leadership, the division expanded nearly seven-fold in patient volume and developed multiple nationally recognized specialty clinics. He is a leader in applying genomic sequencing to clinical diagnostics and founded the MGH Genetic, Phenotypic, and Biologic Sample Repository, now with more than 1,000 participants, enabling global data and biospecimen sharing. He is also Director of the MGH NORD Rare Disease Center of Excellence and MGH Site Director of the Harvard Medical School Genetics Training Program. A dedicated educator, he serves as Course Director of Harvard’s Genetics in Medicine program.

Dr. Sweetser is a founding member of the NIH Undiagnosed Diseases Network and, with Wendy Chung, co-PI of the Harvard Clinical Site. Through the UDN, he has helped diagnose and publish 16 newly discovered genetic disorders and contributed to a >40% diagnostic rate across more than 3,400 patients nationwide. He directs a research lab in the MGH Center for Genomic Medicine and Cancer Center focused on undiagnosed diseases, Pitt-Hopkins syndrome, IQSEC2-related disorder, and leukemia. His work includes iPSC-based disease modeling and precision therapeutic screening.

He earned his B.S. with Honors from Stanford University and his M.D./Ph.D. through the Medical Scientist Training Program at Washington University in St. Louis. He completed advanced training in pediatrics, medical genetics, biochemical genetics, and pediatric hematology/oncology and is board certified in Pediatrics, Clinical Genetics, Clinical Biochemical Genetics, and Pediatric Hematology/Oncology.

Dr. Chung is a clinical and molecular geneticist. She directs NIH-funded research in human genetics of autism, pulmonary hypertension, breast cancer, obesity, diabetes, and birth defects—including congenital diaphragmatic hernia and congenital heart disease. She is a national leader in the ethical, legal, and social implications of genomics. 

Dr. Chung has identified the genetic basis of more than 60 rare diseases. She leads the GUARDIAN study to expand newborn screenings for genetic disorders and advance development of personalized therapies for children with these conditions. Dr. Chung also leads national collaborations to identify the origins of autism and guide impactful therapies and services. Her goal is to enhance understanding of autism contributors, discover how the condition changes over lifespans and identify how to support individuals. 

Dr. Chung has received the National Organization of Rare Disorders Rare Impact Award and is a member of the National Academy of Medicine and the American Academy of Physicians. She earned her BA in biochemistry from Cornell University, MD from Cornell University Medical College and PhD in genetics from The Rockefeller University. 

Daria (Mom) Registered Nurse Brigham and Woman's Hospital specializing in Heme / ONC / BMT

James (Dad) Mental Health Clinician, Granite Recovery Center. Works with people suffering from addiction

Makayla (Sister) 19 year old Sophomore at the University of New Hampshire studying Biology and Genetics. She has had great inspiration for her career aspirations based on what she has experienced being Dylan's sister and as a family with the Undiagnosed Disease Network.

Sydney (Sister) 17 year old Junior at Pinkerton Academy. She is a soccer goalkeeper, currently recruiting for college. She is the 2009 goalkeeper for the state of NH Olympic Development program, ECNL RL goalkeeper for FC Stars and a varsity Goalkeeper at Pinkerton Academy. Dylan loves watching soccer and cheering on his sister and her teammates.

Dylan (our king) 14 yr old student at the Cotting School. He has been absolutely blessed to become out of district placed at this school and become part of such a wonderful, inclusive community. He loves his school and the friendships he has made there. He enjoys playing adaptive Soccer, Basketball and Baseball at the Cotting School. We are proud to say that his Dad and I were his sole advocates in getting him out of district placed from the Derry School District. MTSS2 gene has a large intellectual disability component to it and getting him into the right environment to foster learning was not an easy task but a hard fought task we won. Dylan is in the Upper School at Cotting (technically 9th grade). Dylan's academic abilities include Reading level N (mid 2^nd grade reading level). He is able to decode higher level words, but often does not understand the text he reads. Math able to add and subtract 2 digit numbers, read numbers and place value, and basic multiplication with support. He has a basic understanding of number and quantities. Writing is not preferred for Dylan, but he uses applications in co-writer, google docs, read and write for google. He receives OT, PT, Speech, and Nursing for support services within his school day. 

This event is part of the Belonging Beyond the Diagnosis series and art exhibit in honor of Rare Disease Month.

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We are committed to making this event accessible to all participants. The space is wheelchair accessible, microphones will be used for speakers, and assistive listening devices are available for use. Please reach out to countwayoutreach@hms.harvard.edu if you have any accessibility needs or questions.